International 444 hydro system overheating

[01dually]

So after about 2 hours of heavy field mowing my hydro lines get real hot and after about 4 hours of operation thers a noise under seat, even when impliment is lowered it sounds like hydro system is straining as if ther was still a load on it. Also it will not lift implament up unless I have the rpm"s above 1000 but only when its hot. When cold it lifts fine at idle. I have checked orfice screen and suction screen and they are both clean. I had hydro pump apart a year ago to replace gaskets cause I had engine oil in hydro system and the pump looked ok to me . Any help would be much apriciated thanks in advance

[art]

My htoughts are that you might have a valve being held open or under pressure when not needed. This might happen do to hitch adjustments or just something sticking do to a little extra slop do to use and age.

They will run up to 200 normally and like with all oils and pumps when they are cold is when they normally work the bestas the parts are smaller and the oil is thicker.

[01dually]

Thanks Art, Thats what I was thinking my relife valve stuck open or it needs a shim .

[dieselscout80]

Thanks Art, Thats what I was thinking my relife valve stuck open or it needs a shim .

Did you do anything to fix it?

[01dually]

The only thing I did was set my draft countrol to the heavey position and that seamed to resolve the problem. The brushog that i use for that tractor is very heavy and had the draft set mid way between heavy and light.